1. Field of the Invention
The present invention relates to a photographing apparatus capable of vibrating an optical member to remove dust thereon, and a vibration control method of the optical member.
2. Description of the Related Art
Photographing devices such as digital still cameras and digital video cameras equipped with a charge-coupled device (CCD) with high pixels provide high definition images. A single lens is typically detachably installed in a main body of the photographing apparatus, so that a user may select and use a desired optical system (a lens unit) when photographing a particular object.
In the digital camera, when a lens is separate from the main body of the photographing apparatus, dust floating in the air may enter the main body of the photographing apparatus between exchanging the lenses. In addition, since there are components, such as a shutter and an aperture, that mechanically operate in the main body of the photographing apparatus, dust may be also generated when operating such components. When dust is exposed to a filter surface of the photographing element, the dust is captured on a photographed image.
In order to solve the above problem, digital interchangeable lens cameras have a dustproof member between the photographing element and the optical system to prevent dust from the photographing element and the filter, so that the dust attached to the dustproof member can be removed by vibration.
In the above conventional dust removing method, a frequency of the voltage applied to a piezoelectric element is driven on a resonant frequency of the dustproof member so that dust can be removed. However, since there is a physical limit to a frequency band capable of obtaining a desired step-up rate of a step-up transformer used in a driving circuit of the piezoelectric element, it is difficult to drive the circuit in a wider frequency range.